SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ac6c9a9dc1ddd7072c2d5e039219bbe70026f2e184bb83169c5834e92016b72' 
  AND token = 'TBRvDfVdK7JweIlScTOPDn+VOWszWvNkc38ceS39ALA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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