SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a9967102a3d406fe5ca541f2a3775e450d42698782cbca4f94ab2fb2168cfdb' 
  AND token = 'uzk6WW4645fcA3Mujj8uMAoCwXpE2/FEuDHWP80rSQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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