SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af2f53f6481f34c5b0ad445fd5a3a71b88b37f382591a60f9e65ba01bd646fcf' 
  AND token = 'BjhZDqjHv1twQTld7Le9PSF0e2XX2fk+wzKUEohcc0c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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