SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87a18e22a8b4b49c2ae7e9a0142510d1228f557b5645564a3dd0755b5cf7a0ef' 
  AND token = '0SZXqQx6ly8/BAuLT/Iim1+yrycHO6kbzjrqR+AWZbY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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