SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b00e21da3250df627527b9723cc592b2f18c4308923c5351a49cc7252254c9d4' 
  AND token = 'N6pUza8b7KR/muSSEFfbJFfugiVO+OFQ1cKv3lTIGiQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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