SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e69de5e355cbae8e4fece9d395a037dd9fe876f8874db6669427d0d22e5c38' 
  AND token = 'V/N3K3SICPSWXlHyD7MN4ke6XTjf4MOggDW8SMw9n6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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