SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d3098bc3e1732c5d345fcacb94529043952f69b3470f723601bdda77845345d' 
  AND token = 'd1UaiZ6pVHK3x9YE0TFtOqBwz0fjVX6p8d5Th8zAv4M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}