SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0be683d4d38ed66a1af6fae867b3e6ef591aac6d3c3f1badd52873d59ad3a3ea' 
  AND token = 'p6rv5PZAQ1QfJw7P0pBreP7eBpLMgCZTtw7rLoE9uo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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