SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9531438dfcbba0946b9a70f42cdb11518eef9d4b5b8916dadd5a477eb5c53e2b' 
  AND token = 'kk2t87eqrl0tiqpqViN1Dw8TDeTQydrCX8/pT9j7HCA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}