SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c812c1a2d1c9edea1b61380600f927f3ccb9215ee271024110c2769886f068d' 
  AND token = 'rB2Q1fYsRtQCXdfD8LBPPAgbjBguF7jNOHrZRWRWoRE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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