SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b744b3ecab4f4117875ec6aa281d0cc0e13449b5856e022a6b81c6a1da81979' 
  AND token = 'CisnB3SolCQKZcvaZodkM7r9QXNEdCe/41XsuzyjzJ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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