SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '402b33483b4551a2aa4e12f704caf78e6638ad0c3042826f15935896f07179d6' 
  AND token = '2LHOb7QFR9WERfvbJR4HWcMf0VykycbqdsKfQQDcNQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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