SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b0df8899d00c9587a6c23c44693ccb25dbcb165e0c280f65e5d13eac210e76e' 
  AND token = 'KpYElpARNK6DzUzQf2WQFi4q+hG3I2hr6WBUaHFB4KQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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