SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f739d45fcaa8bce77e7d4969499e24ac77a6b9fececeb0c0f6f9d12ffca53018' 
  AND token = 'yR2FRfW5BpCcq7pTbdA85tVr/SwPGbriZLru+hffU4g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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