SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97ff1d56e51af17c8339ce02f7dae35a1987ad4b1e6093f7cd2a40005aabeeff' 
  AND token = 's2GFqy3oqjOyJiP62RblhvNI6GgQYbo/LzAjQaaB61w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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