SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6127d3ac688c7f36b29e1e0a2eb630a5fcd3ef7fceb9ae28e2b5d04a41d0046f' 
  AND token = 'RWJCXRalKy9Zhv3Kb0LblNXHuLFp//ZO6HjDI4kZGig=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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