SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a091a44c6898e2d2dcbaaebc2e9f9e1435b0530d7e1a991851b0d5e528bc294' 
  AND token = 'siONsxE4YH8GiHCd5EFu8JjG+UyJ68KUgIRqdDWh6jI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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