SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'caa68b37552e6f9cd92aef01a581e46a1b7ce3dd4ffc2498572e881a3b46ad51' 
  AND token = 'sfk7/6A6put/uq3FEy7BfJXCZDSguZi9vxYJoybhYTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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