SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb15fa2d4d43171e393dc05f072708ac5d655dcefddcef5799784c73eff8b781' 
  AND token = 'zjHb7KmK6OFwd6CzlhuRwvUsHqgSyRujmMCYuGq6qjo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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