SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a64d673a10d218116c38514076493226ed017eda2e115c34efbba0bf974333b9' 
  AND token = 'stDcLZ+MjWsex2RyOhUW3ci6X/jHrbIrsz74Tcg4n2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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