SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7e1d4ace1365f17e6d6fc73611b79dab2bb6b5278ed921eaf28455356f9beaa' 
  AND token = 'SdEtk7esQaXHN8faiZyUq8rxXnc818dEACI6tAR22kE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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