SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1233d4c5780fa1ced1896e4b1a5703ce400fd2802092653f6a0f1df78b73fee' 
  AND token = 'fnAyFrytJl5TqoE5iqoxAoGHd7fzWGluPwcgUAsNO1A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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