SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75a70f3299d7eefe15e507adb12358a251fbca75a31a03faa24545151c4cb614' 
  AND token = 'Pc0KR9N5vEuDIlNHTMEmCw26lSjZ8nBD+0ko3FEbEFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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