SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15f3c95518ea8bd7df19c1c2623b6c359685379b776427a82ea8ff4bb86180f9' 
  AND token = 'YdRAQsXW9AGT3PLrqmoeXkwVzRLDR8JhQL+obzB8pXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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