SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a647d5f407d6820a8f331c0c9201e4eed4c07fad96b1b1e9eec632a7339a9717' 
  AND token = 'e7E6z0JRBvKCsEIVerjt3g0bBcnWK0srbu9Hgez+Mu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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