SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6aaff0f5cbe0adc4142dece97b32a8575716933d34d92b1357285cd7634c5dcf' 
  AND token = 'YuTHXbWLy3syzos6tcR4aGQsfHDjDIOcv0H4Wq+scVQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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