SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f65def9512eaf0b1d0dbe8aec13b17df6a6bce956ba717602f838810e7df6c7a' 
  AND token = 'IDxyxnmggPfPSCzeVIuw7X7UIhmdlp0OjAPc+C9Xz/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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