SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a0752bfcaa09266c566dc9614ccca825e57ce9deccf71f9147cc7592266e057' 
  AND token = 'IaASPLBqj89DOI85sInGFfvJK6urEtTowCCSb/vnCos=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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