SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf6edf7b479505f22abd4cce986e46dc462d9416da2c46b35a8c2c69dfcfcb2b' 
  AND token = 'C3yMASgKgqGOlGBsXyiR52j/xmhIJKB9phhurg7MDOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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