SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0df492841374f7b2038b365057337cfe4340f6d0f888afc4c7e3ff4a572d9fa5' 
  AND token = 'rI1mXyi9pF0Myaj1w7M1JVBdutD+/emMsAPWYoJvqKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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