SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd314c0daf6065ef96d5d11af5e7ac61214c3df9f50761526eb305d504defe100' 
  AND token = '0pkhrk0Ywe8C/mowm1ce7YqjspTw51hegcN40Huyj2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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