SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c314fc6afd3d12fd949c25bfd9ac28f5a26b483d10dab18708537ae992b7bac' 
  AND token = '4+l5Kuu7dYI7fKdBdGC+6O7wp8m+B1r0R/SnyP5VglY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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