SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'ac340ff3f84a22f2dca2951c28fa1144559505f0fad672478ce7a02be8a691cb' 
  AND token = 'SgK6akEULfKVo2baLQxI3joJS/oXpoMgjnJzPyUruZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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