SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79c424a905940652dc3447a0c344b13a1d24da37232920ea547fbedfb90c7f8a' 
  AND token = 'qQbJLZwenVtCTf8DZRI5pCWyL3YVJZbb7qmyICe1/jM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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