SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b7be7b69c288901b41344bb4673615d44872595dc845c16f23f48e8988e9a4e' 
  AND token = '+Vv/l/9hG4ssBG6h9wp4w/v0lEjLdhIYo1rWQ4cmIcU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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