SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '95b9ed83a833d927cde0565ba6f6005b0864c00a13d85573b4259db9f84bdb8c' 
  AND token = '8BJmpcOeAX8K4BsT5mthSf92b/KxgDZeCJCRXXZ7EJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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