SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ea0f9efb49382043aee96c0af61b16734a73f9f147bfd336627b5673cd3ed4' 
  AND token = '6bIOqpStJAGTac/fpC6Syt1msHNecGL4i0EzStegAhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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