SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b0f319a78626ac8478fb975e9cebfba527a937c4e9fd4d6f70f387c49c6d269' 
  AND token = '61qzWiye2FrBqh7zneI+1M8sJ7lBGPwfmm3W6X+/12Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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