SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c6641984b75d7075a9e9fec807f3955a2be020dabfc10b219774fe208d1a793' 
  AND token = 'MCgTqgPE76w+gE9O87HXAO3cJkS2s4+V8U/EBZhkKlQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}