SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0221ee52add24f778927be00fcf66f60499c63932765b25c48ac5d4f70c91384' 
  AND token = 'PxtB7Jk1tr+7WA1t+slgNVeYjP8EEeJDrrL7A4ioruY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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