SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b88fd4578b937c1a9b0a205a3930cb7e7853e73f77fd63c0b054b217bcf62a5' 
  AND token = 'LjaY2tYywJkGI2+3K6Gx/qHC+BzKPNkLMi1ae1A/XR4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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