SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87720f9ec2dc0c875a417d30cc9918dde19beafbc9039eaab321163aaf3d33e5' 
  AND token = 'ta4OWzhIjaErCAy2Kxim2H34eonwvnE+hbCXe83dEG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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