SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '407a5c17e553fdc7dfd60d7a09add7c22e3ea80efcb2ab1a12861c19e6f49ae7' 
  AND token = 'ck9pIB4hvvGFTgF1rhTkOolU4JcUqn5UnPtQCAgtZks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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