SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e9d37066c7e3b71cf15639ffcc2ba2ae633ad6064c5f2c5855b2fd7d6921f2c' 
  AND token = 'Yhm6yg67YH9BRy7E0cMFvAxTDfhf9DcdTMCmMA02S/E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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