SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e61788b02e4520bb4921528a80e1a9a6f9ee659b4df4739eb7b352073bf626d9' 
  AND token = 'wk+SJS6rqjoS2+9xUZlfpVqTaq3pDJ9+TKtzEqOQHl8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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