SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387f5448d7350847f905bc510a2bb535e7761fd60c53912098a44bbc19d3853a' 
  AND token = 'JYvpU9C0OL/yqYF/ISjDDSOcnQyYrdfSQ/2qKvqdCnY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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