SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c5a096253cb0ad348bf27151b290647434a4f8f6999e375e0812eafa7426cd7' 
  AND token = 'QNLkCngjwBwF0ev+AFI6A6YZgy+KiQwWbqq0/pX53mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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