SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42d163b8047b1d66bcb751f6cabeff795600d63c5847a2a574fe94038096cb59' 
  AND token = 'pdCT4CVTlzfNEnTAAjo3empGdh78BovLQZc0/REbIec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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