SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f584fba500c8b868c031ce579dc956a1207eb19b7dc9554e7256f39f0c8a9873' 
  AND token = 'fYDWTD99sZTn1OSKJkfCAoDo1awvJYUOgRUglgU2adA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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