SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '616eb840b1b71d022ef06dbdd00ac818af8e874cdaa655b2af2dcddc08e97be6' 
  AND token = 'puJr1MdyGCQZY6o+gGpuZwV9XlVOfNU1omrLgRd0Mo4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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