SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4731edf9db1ae435a2cb52944caf8a7a91720c273487ceb29e0cf3c3cfdf8b3c' 
  AND token = 'dQ9QXjBiD68Zw3cir8rFa38XRIXL2OGxShtEjHk6rcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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