SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f252de038f3ed2299a325e950fcdf0a057339f8532eeebd3c77480d048a7cd5' 
  AND token = 'LIkaOa3pno0WUIr6INjUbCti5zmoEkh7rCBVnldrRWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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