SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4799eb7dc41fe0cd25f3e0755fb9b33b9d80b0e5398970732555ba04b805503' 
  AND token = 'Chfw3HVARggAKZU6kVaFi1w+cPqB2UZh5/dZvmiwHqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}