SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2640f15683a784f087e5bb3dafc972862e55688825162657db62013371e649f5' 
  AND token = 'WrfxswfqxDVfvITqWjXZ3z/Aj59GRP9V5AO3lyskCC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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