SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '070b7d91bf053a76302f2aef6202edef2970d49cc07d08280791fdb037103126' 
  AND token = 'QPZxhEoGEw9JVotrHS9+j29JKNZMTrw8pbo2x8h3Z58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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