SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64a526c8b7c59fd1ad7094c0730d2701374b23ad79ca1682b7265f0223972fb1' 
  AND token = 'myHc3Kj+p8lRLwdJczROiozjHovIa+9+nDCZwTmzvok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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