SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53a64fb351acb6a4098ff4ca4469582545be22a383067bdf1d29e165adadac52' 
  AND token = 'WqA6RlCf4rHNPdkpwUg6aJIlujRACie8EikxZRXJtZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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