SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce876557daa06f1483607a765f7c3cd3d353356ef79b74c125c357e113dfff0d' 
  AND token = 'kUksfQX8M90m6ecLLO27ZOCjm5CJtsFIvJ0BqFuNf9s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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