SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbfc64590d358356371016b2a5fc564f2fcd148d0f95cec5deae55d7c2407370' 
  AND token = 'GrpcNMY1KfrYV6+658FyHqjozLQWQmdFMANY4CunvrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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