SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8457a9a0aea88345e041e15aa2935efbbff69b7e2e2b130eedf6997c5fc4cb44' 
  AND token = 'AgZmhlZHmDiqgzvDIptf/GCyJgRJCXDzPb949MSYMtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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