SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f75d428b91406476547b868583692c7651c9b806a6cff4fbb12c8bd05195cef' 
  AND token = '89RfBRDWjNOrribB0OnHIKA7iSDSQqgEEl87J6VypE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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